Time Between Statuses Script Field

Trying to fix a really old scripted field for time between statuses. I'm not at this level of complexity (I just did an Age field, but it took a lot of trial and error). Any ideas where line 16 went wrong? I am getting Static Type Checking error on L16,C17 for cannot cast java.sql.Timestamp to double and doulbe#minus(java.sql.Timestamp)